Multilayer, particularly singly or multiply folded printed products, e.g. magazines, must generally be cut or trimmed on at least one and usually on two or three sides. In the case of industrial flow-line production of such printed products, which are generally conveyed away from the rotary press in the form of a scale or stream flow, every effort is made to integrate the cutting process into the dynamic production process, i.e. to cut at a speed which matches the maximum rotary press capacity of e.g. 80,000 copies per hour.
Numerous cutting means are already known. Thus, e.g. Swiss patent 650 967 and European patent 0 017 878 in each case disclose an apparatus for the lateral cutting of paper sheets, in which the sheets are conveyed in a scale or imbricated flow on a planar conveyor belt against one or more rotary cutting knives or blades and are laterally cut by the latter. Although this generally leads to acceptable cutting results, the said apparatuses suffer from certain disadvantages. Thus, it is difficult and complicated to precisely orient the individual printed products in the scale flow. In addition, in the latter a gap is formed between the individual products and the substrate, which particularly in the case of thicker articles, leads to tears in the cutting edges, particularly of the first pages, as well as to irregular cutting tracks. If the products are not only to be cut on the sides parallel to the conveying direction, then the scale flow must be turned by 90.degree. or the printed products must be individually turned, which is prejudicial to the optimum spatial arrangement of the production line and is also technically complicated.
Knowing that cutting in a scale flow suffers from various disadvantages and normally does not satisfy the need for a high-quality cut, the Applicant has already made a number of proposals, in which the printed products are not cut in the scale flow.
In conjunction therewith, Swiss patent application 4876/85-4 (now Swiss Patent 668,216) discloses an apparatus for the three-sided cutting of printed products with a path revolving continuously about two drive wheels and having a plurality of compartments, each serving to receive a printed product. Along the straight portions of the rotary path are positioned three cutting devices with a plurality of cutting knives and counterknives arranged pairwise parallel to the path and past which the printed products are moved and correspondingly cut. Fundamentally this leads to a good cut, even in the case of thick printed products However, it has proved disadvantageous that the precise, straight guidance of the rotary path absolutely necessary for an exact cut is technically complicated and that the cutting devices require a relatively large amount of maintenance.
A further apparatus according to U.S. Pat. No. 4,038,893, in which the printed products are individually cut, comprises a rotary bucket or compartment wheel, whose individual buckets or compartments each receive a single printed product and which is provided with movalbe knives operable by means of common control cans and counterknives cooperating therewith. This apparatus is relatively complicated in construction and therefore expensive to maintain.
It has been found that the known cutting procedures in the case of dynamic high-capacity processes do not meet the quality demands, or only do this at the cost of high constructional expenditure. However, it is never possible to achieve such high cutting qualities as in static or alternating processing operations, where highly developed cutting procedures are known ensuring excellent results through the careful guidance of the cutting forces. Thus, e.g. complete paper packs resting on a fixed substrate acting as the counterknife are cut with excellent accuracy by a vibrating or cutting knife, which cuts the product on a precisely defined path (e.g. logarithm form).